Transcript PowerPoint Presentation - Nerve activates contraction

2
Basic Chemistry
PART A
PowerPoint® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University
ESSENTIALS
OF HUMAN
ANATOMY
& PHYSIOLOGY
EIGHTH EDITION
ELAINE N. MARIEB
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Matter and Energy
 Matter – anything that occupies space and has
mass (weight)
 Energy – the ability to do work
 Chemical
 Electrical
 Mechanical
 Radiant
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Composition of Matter
 Elements
 Fundamental units of matter
 96% of the body is made from four elements
 Carbon (C)
 Oxygen (O)
 Hydrogen (H)
 Nitrogen (N)
 Atoms
 Building blocks of elements
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Atomic Structure
 Nucleus
 Protons (p+)
 Neutrons (n0)
 Outside of nucleus
 Electrons (e-)
Figure 2.1
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Identifying Elements
 Atomic number
 Equal to the number of protons that the
atoms contain
 Atomic mass number
 Sum of the protons and neutrons
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Isotopes and Atomic Weight
 Isotopes
 Have the same number of protons
 Vary in number of neutrons
Figure 2.3
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Isotopes and Atomic Weight
 Atomic weight
 Close to mass number of most abundant
isotope
 Atomic weight reflects natural isotope
variation
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Molecules and Compounds
 Molecule – two or more like atoms combined
chemically
 Compound – two or more different atoms
combined chemically
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Chemical Reactions
 Atoms are united by chemical bonds
 Atoms dissociate from other atoms when
chemical bonds are broken
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Electrons and Bonding
 Electrons occupy energy levels called
electron shells
 Electrons closest to the nucleus are most
strongly attracted
 Each shell has distinct properties
 Number of electrons has an upper limit
 Shells closest to nucleus fill first
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Electrons and Bonding
 Bonding involves interactions between
electrons in the outer shell (valence shell)
 Full valence shells do not form bonds
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Inert Elements
 Have complete valence
shells and are stable
 Rule of 8s
 Shell 1 has 2
electrons
 Shell 2 has 10
electrons
 10 = 2 + 8
 Shell 3 has 18
electrons
 18 = 2 + 8 + 8
Figure 2.4a
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Reactive Elements
 Valence shells are not
full and are unstable
 Tend to gain, lose, or
share electrons
 Allows for bond
formation, which
produces stable
valence
Figure 2.4b
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Chemical Bonds
 Ionic Bonds
 Form when electrons are completely
transferred from one atom to another
 Ions
 Charged particles
 Anions are negative
 Cations are positive
 Either donate or accept electrons
PRESS
TO PLAY
IONIC BONDS ANIMATION
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Chemical Bonds
 Covalent Bonds
 Atoms become stable through shared electrons
 Single covalent bonds share one electron
 Double covalent bonds share two electrons
Figure 2.6c
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Examples of Covalent Bonds
PRESS
TO PLAY
COVALENT BONDS ANIMATION
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Figure 2.6a–b
Polarity
 Covalent bonded
molecules
 Some are
non-polar
 Electrically neutral
as a molecule
 Some are
polar
 Have a positive
and negative side
Figure 2.7
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Chemical Bonds
 Hydrogen bonds
 Weak chemical bonds
 Hydrogen is attracted to negative portion
of polar molecule
 Provides attraction between molecules
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Patterns of Chemical Reactions
 Synthesis reaction (A+BAB)
 Atoms or molecules combine
 Energy is absorbed for bond formation
 Decomposition reaction (ABA+B)
 Molecule is broken down
 Chemical energy is released
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Synthesis and Decomposition Reactions
Figure 2.9a–b
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Biochemistry: Essentials for Life
 Organic compounds
 Contain carbon
 Most are covalently bonded
 Example: C6H12O6 (glucose)
 Inorganic compounds
 Lack carbon
 Tend to be simpler compounds
 Example: H2O (water)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Biochemistry: Essentials for Life
 Organic compounds
 Contain carbon
 Most are covalently bonded
 Example: C6H12O6 (glucose)
 Inorganic compounds
 Lack carbon
 Tend to be simpler compounds
 Example: H2O (water)
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Important Organic Compounds
 Carbohydrates
 Contain carbon, hydrogen, and oxygen
 Include sugars and starches
 Classified according to size
 Monosaccharides – simple sugars
 Disaccharides – two simple sugars joined by
dehydration synthesis
 Polysaccharides – long branching chains of
linked simple sugars
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Important Organic Compounds
 Lipids
 Contain carbon, hydrogen, and oxygen
 Carbon and hydrogen outnumber oxygen
 Insoluble in water
 Neutral fats (triglycerides)
 Source of stored energy
 Phospholipids
 Form cell membranes
 Steroids
 Cholesterol
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Important Organic Compounds
 Proteins
 Made of amino acids
 Contain carbon, oxygen, hydrogen, nitrogen,
and sometimes sulfur
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Proteins
 Account for over half of the body’s organic
matter
 Provides for construction materials for
body tissues
 Plays a vital role in cell function
 Act as enzymes, hormones, and antibodies
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Important Organic Compounds
 Nucleic Acids
 Provide blueprint of life
 Nucleotide bases
 A = Adenine
 G = Guanine
 C = Cytosine
 T = Thymine
 U = Uracil
 Make DNA and RNA
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Nucleic Acids
 Deoxyribonucleic acid
(DNA)
 Organized by
complimentary bases
to form double helix
 Replicates before cell
division
 Provides instruction
for every protein in
the body
Figure 2.18c
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Important Organic Compounds
 Adenosine triphosphate (ATP)
 Chemical energy used by all cells
 Energy is released by breaking high
energy phosphate bond
 ATP is replenished by oxidation of food
fuels
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings